Exhaust machine



July 10,1928. v v I Imago? J.M. VAN DER PQEL EXHAUST MACHINE Filed April 8, 1926' s Shee'ts-Sheet '1 Q M ,r m m v MA T Johannes MAA cl. Poe! Jul 10, 19 2s.

I 1,676,302 J. M. VAN DER POEL EXHAUST MACHI NE Filed April 1926 3 Sheets-Sheet 3 ITWVEETWCOT: Johannes M. v. d. Foel; by His AttoW-neg.

JOHA NNES MARINUS VAN DER POEL, 0F EINDHOVEN, NETHERLAE'DS, ASSIGNOR GENERAL ELECTRIC COMPANY, A CORPORATION OF. NEW YORK.

EXHAUST MACHINE.

' Application filed April s, 1926, Serial No. 160,708, and in the lqe t-herlands June 2, 1925.

This invention relates to exhaust machines of the type which has an' intermittently rotating carrier for the vessels to be exhausted, and a number of highvacuum pumps moving with the carrier, the heads or holders 'for-the vessels to be exhausted being attached to the carrier and each head connected to a high vacuum pump. Exhaust machines of this general type have been used, especially in exhausting incandescent lamps,'radio tubes, and other electrical apparatus, the vessel to be exhausted being directly connected to the high vacuum pump during the entire process of exhaust. Usually a reservoir or bufler chamber common to all the high vacuum pumps is inserted between them and the rough vacuum piping to act as a hacker for the high vacuum pumps and preserve thefvacuuma vOne drawback of suchexhaust machines is that when a.

leak vessel is being pumped the exhaust of all tiie other vessels in the device becomes very diflicult. The present invention overcomes this difiiculty by providing means to con nect the hacker pipe between each high vacuum pump and its backer or rough vacuum pump separately to the rough vacuum pump before the final exhaust is started, and then to seal 'aifr tight the backer pipe of each pump during final exhaust.

According to the invention the backer pipesof the high vacuum pumps are ,con-

nected to a valve disc which moves with the rotatable carrier and which cooperates with a stationary valve seatv in such a way 'that in at least one positionof the rotatable car rier the hacker pipe of each high vacuum pump is connected to the backer or rough vacuum pump. :By keeping the backer or rough; vacuum sides of the high vacuum umps entirely separated fromeach other, a eaky vessel on the exhaust machine cannot have any detrimental effectupon the other vessels which are then being exhausted on the machine. Also it is no longer necessary to insert valves between the vessels to be exhausted and thehigh vacuum pumps. Preferably only one vessel to be exhausted is connected to each high vacuum pump in anexhaust. machine embodying this invention.

Of course the air which is pumped out of the vessels to be exhausted by the high vacuum pumps after the backer pipes are closed will tend to increase the pressure of 'ly used 'begin to operate the hacker vacuum, but in accordance with the inventionthe volume ofthe backer vacuum pipe between the high vacuum pump and the valve, disc is made so large'thatthepipe serves thepurpose of a hacker vacuum pre server which keeps the hacker vacuum pres sure below themaximum at which the high vacuum mercury vapor jet pumps common-1 Also in accordance with the inventionv the backer vacuum pipes are formedasflarge spirals or helices, which may be cooled by the cooling water he placed entirely outside of the pump. In

'case a high vacuum mercury vapor jet pump should be connected directly to the atmos phere on account of a leak in the vessel to be exhausted the mercury in the pump would begin to bubble very strongly, and would tend to pass up into the hacker vacuum pipe. By making these -pipe connections uneconomically.

of the pump or they may 7 large the liquid mercury that drops back and the mercury vapors that rise will be able;

to pass each otheig'and the danger of air, pockets in the hacker vacuum pipewill be avoided. The pipes should be cooled'in order to condense any mercury vapor sucked vthru with the air.

At the start ofthe process of exhaustion the backer vacuum pipes of the high vacuum pumps may also be connected to the vacuum system, but it will generally be bet ter to connect'the backer vacuum pipe rough vacuum pump in order to insure a I good vacuum on the backer vacuum side. of

the high vacuum pumps at the start of the exhaust process, as in that case if metal .vapor jet pumps are used these pumps need not be heated as much as though the backer vacuum were poor, and, therefore, will work more economically. than usual.

The fvalve system of the exhaust machine may, in accordance with the invention, be made witha rotating valve disc provided with asJ-many ports as thereare high vacuum pumps ,on the exhaust machine, ..the backer vacuum pipesof the high vacuum pumps vterminating at these ports, and a stationary valve seat fitting air tight to the rotatable valve disc and having one or more. ports connected to rough vacuum pumps and registering with the ports in the rotating Valve disc when the intermittently rotating carrier is standing still. To prevent leakage into the valve, one or more annular slots may also be made in the cont-acting surfaces.

of the valve disc and valve seat to surround the ports in the surfaces,.these slots being connected to a vacuum pump. r

In the attached drawing which shows one form of exhaust machine embodying the invention and adapted forexhausting the bulbs of incandescent lamps, and similar articles, Fig. 1 is a plan view of the" machine; Figure 2 is a vertical section along the line 1111 in Figure 1; Figure 3 is a vertical section of the mercury vapor jet or condensation pump which serves in the exhaust machine, and Figure 4 and --air tight connections between the exhaust Figure 5 are respectively a vertical section and a plan of the valve used in the machine shown in the drawing.

The particular machine shown in the drawing is assembled on a table 1 supported on tubes of the bulbs to be exhausted and the high vacuum tubing. A protecting disc 11 is placed over these heads which is attached to the rotatable carrier 3 by means of bolts 12. (Fig. 2

Each head is connected to the exhaust pipe of a mercury vapor condensation pump by meansof high vacuum tubing 23 (Fig. 2). The mercury vapor condensation pump is provided with a boiler 26'.(Fig. 3) for the mercury, or other metal with low melting point, and a heating coil 27 isplaced inside of the boiler. The mercury vapor produced by the heating passes up thru the vapor conduit 28 and is deflected thru the holes in this conduit downward thru the ring shaped jet nozzles 29 and 30. .The mercury vapor thereby takes the air molecules from the vessel to be exhausted along with it thru the exhaust pipe 25 and condenses against the wall of the pipe 25. The liquefied mercury drops into the chamber 31 from which it is drained into the supply tubes 32 and 33. The air that was drawn by the vapor is sucked off thru the spiral pipe 34 which leads out of the cover plate of the chamber 31. To speed up the condensation of the mercury vapor the pipe 25 and the spiral tube 34 are surrounded by a water jacket 35 thru which the cooling liquid, for instance water, may be made to flow. .The boiler 26 is surrounded by a heat insulating cover 36.

The backer vacuum pipe 38 (Fig. 2) is a as the high vacuum pump continuation of the spiral tube 34 andin order to increase its volume part of it is wound as a sp ral.

The backer vacuum pipe is connected air tight tothe rotating valve disc 7 (Fig. 5) which is attached tothe tubular shaft- 6 by means of aset screw 39 (Fig. 4).

The air tight connection "between the hacker vacuum pipe and the valve disc 7 may be made bymeans of a gasket 40, made of rubber or similar elastic product," which is pressed around the pipe 38 by .means of a nut 41. v I

VVhe-n the carrier 3 revolves intermittently,

taking the valve disc 7 along with it, the

hacker vacuum pipe 38 comes into position opposite a port 42 in the stationary valve seat'8. This port is connected to a rough vacuum pump or to the rough vacuum piping of the shop through a rough vacuum pipe44. In all other positions the port 42 of the valve disc 7 is closed by the blank surface of the stationary valve seat 8 and the backer vacuum sides of the metal vapor con-' densation pumps 31 in those positions constitute an enclosed space.

In order to obtain a good air tight fit of ,the valve the stationary valve disc 8 isv provided with a ring shaped slot 45 (Fig. 5) which is connected to a vacuum pump by means of aport 46. v

The cooling water is supplied to the jacket 35 of the metal vapor condensation pumps by means of the inlet pipe 50. This pipe has a water tight connection with the internnttently rotating shaft 49 and terminates in a chamber in this shaft. From this chamber the water supply pipes 5l take the water to the jackets 35-. The water is drained thru the outlet pipes 52 into a stationary tank 53 from which it can be removed. This tank may as a matter of convenience be mounted on pedestals 54.

The carrier can be made to rotate intermittently in the usual wayby well known mechanism not shown in the drawing, and of which only a gear 68 is indicated, which may be driven by an electric motor. The shaft of this gear carries an arm 69 on the end of which there is a roller 70 meshing in the slot 71 of the carrier 3 to rotate the carrier intermittently.

The drawing shows a, practical embodiment of the invention in which seven exhaust heads are placed on the rotatable carrier,-

be exhausted is placed with 'its exhaust tubein a head 10. In the position B the backer vacuum pipe of the corresponding condensation pump is connected to the port 42 of the stationaryvalve disc 8. The backer vacuum space of the pump is exhausted and the condensation pump starts to operate. It shouldbe noted that the condensation pumps must be designed as shown in F igure 3 of the drawing to operate both when .full of air and when the backer vacuum side is suddenly connected to a good vacuum. A large amount of vapor will suddenly be formed when the backer vacuum side of the pipe is connected to the rough vacuum pump 44, but the metal vapor or the condensate are preventcd from being taken along into the backer pipe by the annular chamber 31 inwhich an appreciable amount ofliquidmetal can collect, and also by the spiral backer vacuum pipe which is placed inside i is enclosed by an oven 81. This oven is at;

, gasburners 82 and .83.

-e'awatcr cooled .jacket. If metal vapor "..should enter the tubing 34 it will be con-- d'ensed there and it will drop back into the a *325 annular chamber 31. r

. In the position B the'bulb to be exhausted tached to the table 1 and is provided with In the positions C, D, E, F and the port 42 of the backer vacuum pipe 38'is closed by the blank surface of the stationary.

valve seat 8. The backer'vacuum side of the high vacuum pump is now closed. Gases exhausted from the bulb by the metal vapor jetsare delivered to the backer vacuum pipe I and accumulate in the backer pipes 34' and 38. Of course, care has to be taken to make the volume of the backer pipes 34 and 38 to exhaust the hacker vacuum pipes of the movable high vacuum pumps thoroughly great enough so that the gases which ac-- cumulate in the closed backer pipes during,

the final exhaust of the lamp or similar vessel do not cause the backer pressure in those pipes to-exceed the backer pressure at which the high vacuum pumps'no longer operate satisfactorily. On the other hand,

however, it is desirable to use. a high vacuumpump which can operate against a rather' high backer vacuum pressure, such as the mercury vapor condensation pump of Fig. 3,

which has two annular nozzles in series.

This type of high vacuum .pump can operate satistactorily'even against a hacker vacuum pressure of about 20 mm. of mercury. Considerations of economy, however, makes it necessary to keep the backer vacuum pres! sure of the movable high vacuum pumps as low as possible, and, therefore, it is advisable when they are in the'position B.

Red phosphorus is often used in vacuum lamps to improve the vacuum of the-lamp. The phosphorus is introduced, for instance, by either dipping the filament in a suspen- "easily, as, for example,

' of'final pumps mounted sion of phosphorus or by spraying it on the filament. When such lamps are being exhausted some vapor of phosphorus is always carried along, and partially condenses in the mercury vapor nozzles of the mercury vapor condensation pumps, partially clogging the nozzles, and causing bad operation or noop-v eration at all of the pump; Therefore, the

metal vapor condensation pumps should'be made so as to be cleansed internally very by making the cups 29 and 30 of Fig. 3, where the nozzles point downward, removable. In the position G the bulb is sufliciently exhausted and can besealed off. After this sealed oif exhaust tube a new lamp can be inserted in the head 10.

What I claim as new, and desire to secure by Letters Patent of the United States, is:

1. An exhaust machine comprising an intermittently rotatable carrier having a pluralityyof exhaust heads, an equal number -on and; movable with said carrier-and each directly connected to a corresponding exhaust head, a rough pump toact as a backer for said final pumps,

'ba'cker pipes on the outlets of said final pumps, and means for connecting each backer pipe in succession to said rough pump and thensealing said pipe from said rough pump at a point remote from said final pump whereby each final pump discharges into an evacuatml reservoir formed by said sealedbacker pipe. I

2. An exhaust machine comprising an 'intermittently rotatable carrier having a lu-"" rality of exhaust heads',a plurality of nal pumps mounted 'on and movable With'said carrier andeach directly connected to a corresponding exhaust head, a'roughpump to act as a backer forsaid final pumps,

backer pipes on'the outlets of said final pumps, and a valve rotatable with said car rier for connecting said rough pump to each,

correspondin-gexhaust head, a rough pump to actxas-a backer forsaid final pumps, backer pipes on the outlets of said finalpumps large enough to act-as backers for. said final pumps when evacuated by and sealed off from said rough pump, a rotary valve disc-movable with said carrier and" havinga plurality of ports corresponding to said final pumps and connected to said' 89 the lamp. can. be removed by hand or mechanically and after having removed the backer pipes at points remote from said final pump, and a valve seat cooperating with said valve to connect each of said ports to said rough pump at one position and to" seal said port at subsequent posit-ions of said CRI'I'ICI'. v

4. An exhaust machine comprising an intern'iittently rotatable carrier havinga plurality of exhaust heads, a plurality of'final pumps mounted ,on and movable with said carrier and each directly connected to a corresponding exhaust head, a rough pump to act as a backer for said final pumps, backer pipes of large diameter shaped into a helix and connected to the outlets of said final pumps. and a valve rotatable with said carrier to control at points remote from said final pumps the connections between s aidrough pump and said backer pipes to connect each backefipipe to said rough pump in one position andto seal it in subsequentpositions.

5. An ,exha'ust machine comprising an'intermittently rotatable carrier having a plurality of exhaust heads, a plurality of final pumps mounted on and movable with said carrier and each directly connected to a corresponding exhaust head, a rough pump to act as a backer for said final pumps, a

backer pipe connected to the outlet of each final pump and of suificient capacity to preserve when exhausted and sealed a hacker vacuum during exhaust by the final pump of the vessel in the exhaust head, and a valve between said backer pipes andsaid rough pump having ports connected to said backer pipes and actuated by'said carrier to first connect each backer pipe to the rough pump and subsequently seal said pipe at a point remote from said final pump during the ex.- haust of said vessel by the final pump.

I 6. An exhaust machine comprising a movable exhaust head, a final pump connected directly to and movable with said head and discharging into a hacker pipe of sufficient capac1ty when exhausted to act as a hacker tor the final pump, a stationary rough pump, and means actuated in synchronism With said head to automatically connect said pipe to said pump during a portion of the travel of said head and to seal said pipe at a point remote from said final pump during the remainder of the travel of said head.

In witness whereof, I have hereunto set my hand this twenty-fourth day of March, 1926.

JOHANNES MARINUS van der POEL. 

